This application brings together the Inter-university Consortium for Political and Social Research and three leading centers of population research (The Carolina Population Center, the Minnesota Population Center, and the Population Studies Center at the University of Michigan) in response to RFA-HD-03-032, "Infrastructure for Data Sharing and Archiving." These institutions will provide support to investigators funded by the NICHD Demographic and Behavioral Sciences Branch (DBSB) for data sharing and data archiving, with special attention to complex data and data that require special security. Our goal is to support investigators and the research centers in which they work without taking over their desire to and responsibility for maintaining and disseminating the data they collect. Specifically, the project will (1) provide investigators with tools that will enable them to disseminate public access versions of their data; (2) provide investigators with tools and strategies for the dissemination of restricted-access data (3) assist investigators in ensuring that potential users can locate their data, get support in all the stages of acquisition and use, and receive appropriate training in data use; (4) provide long-term secure archiving of public-use and restricted use data, in order to ensure that the data are permanently preserved for future use; and (5) improve the science of data sharing and archiving through a program of research and development in key areas.